Adsorption and desorption kinetics and phosphorus hysteresis in highly weathered soil by stirred flow chamber experiments

Soil and Tillage Research, 162 (2016) 46–54

http://dx.doi.org/10.1016/j.still.2016.04.018

Soils with a high weathering degree present great difficulties for management of phosphorus (P) fertilization due to their high adsorption rates. The magnitude and velocity of the P retention phenomena in these soils is still poorly understood and has great importance to effective management of soil phosphorus. The objective of this study was to evaluate the adsorption and desorption kinetics and phosphorus adsorption irreversibility (hysteresis) in highly weathered soils. For this purpose, we selected four soils: Xanthic Ferralsol-1 (FR-1), Xanthic Ferralsol-2 (FR-2), Rhodic Ferralsol (FR-3) and Hortic Anthrosol “Terra Preta de Índio” (AT). Adsorption followed by desorption experiments in Stirred flow chamber were performed. From obtained data, parameters related to P kinetics were estimated, considering the presence of two types of adsorption and desorption sites (fast and slow), estimating also the hysteresis index. It was observed that FR-2 and FR-3 showed higher P adsorption and most of the adsorbed P was at first 100 min of evaluation. Furthermore, in FR-1, FR-2 and FR-3, approximately half of adsorption occurred by rapid sites (F which is the fraction of fast sites ranging from 0.45 to 0.55), while AT adsorption was lower (qmax = 48.95 mg kg−1) and occurred slower (F = 0.33). In FR-2 and FR-3, between 71 and 72% of adsorbed P was not desorbed, while in AT, only 11% of P was irreversibly adsorbed. The P kinetics in highly weathered soils proved to be a process governed by the fast sites on adsorption and slow sites on desorption, resulting in high levels of hysteresis.

Dernières nouvelles de 42 vieilles parcelles Indicateurs d’évolutions pédologiques infra-centenaires en Néoluvisol de lœss nu, sous contrainte d’applications continues de matières fertilisantes

Étude et Gestion des Sols, 23, 2016, 143-162

Ce travail présente un bilan des impacts de 85 ans d’apports d’engrais chimiques N, P, K, d’amendements basiques et organiques sur la composition et les propriétés d’un Néoluvisol de lœss, en comparaison à des situations témoins sans apport. Cette expérimentation de longue durée est menée depuis 1928 en sol nu dans le dispositif des 42 parcelles à l’Inra de Versailles. Le bilan repose sur les résultats analytiques d’échantillons collectés en 2014 dans l’ensemble des horizons de surface. Les résultats sont confrontés à des données disponibles du sol initial de 1928. L’objectif est de préciser la nature et l’ampleur des évolutions physicochimiques, induites en moins d’un siècle, et d’identifier les processus pédologiques qui en sont à l’origine.

En absence d’entrée de matières organiques (MO), de forts contrastes s’observent en fonction de la nature des apports minéraux, mais aussi dans les parcelles témoins : en 2014, d’une parcelle à une autre, l’écart maximal de pH est de 5,3 unités (3,5-8,8) et la CEC varie de 5,2 à 14,4 cmol+/kg. La garniture cationique varie de plus de 98 % de Ca échangeable dans les sols chaulés, à plus de 96 % d’Al échangeable dans les sols acides. Le carbone organique a perdu 50 à 75 % de la valeur initiale en 1928, et les teneurs en argile s’étendent entre 13 et 20 %. Des teneurs significatives de Mnéch s’observent dans les sols denses, alors que Feéch est détectable prioritairement dans les sols acides. Par contre, sous amendement de fumier, l’ambiance physicochimique est très différente, notamment par l’abondance de C organique (43-50 g/kg) et une forte valeur de la CEC, supérieure à 22 cmol+/kg.

La nature, l’ampleur et la diversité des propriétés physicochimiques enregistrés dans les horizons de surface des sols des 42 parcelles en 2014 témoignent de différents processus pédologiques en jeu, actuels ou dans le passé. Dans les sols témoins, sous la seule contrainte de la minéralisation progressive des MO et des conditions atmosphériques, les propriétés et la composition ont considérablement changé : une acidification de 1-1,5 unités de pH, la lixiviation d’une proportion notable de cations bivalents et l’apparition de quantités significatives d’Al échangeable sur le complexe d’échange, une baisse de la CEC et une perte d’argile de 2 à 3 %. La migration d’argile, l’argilluviation, processus caractéristique dans les luvisols, apparaît amplifiée sous traitements ‘monovalents’, notamment sous apport de Na où la perte d’argile par lessivage peut atteindre jusqu’à 5 à 6 %. Sous apport de K, la perte d’argile est moindre, liée à un processus d’illitisation des particules de smectite par rétrogradation du K. De plus, les apports de phosphate naturel ou de superphosphate semblent également favoriser la migration d’argile, alors que les amendements basiques et de fumier limitent, voire stoppent le processus. Dans les traitements ‘acides’, sous apports d’engrais ammoniacaux ou de sang desséché, les cations échangeables initiaux (Ca, Mg, K, Na) ont été quasi-totalement lixiviés, et remplacés par l’Al. La forte aluminisation du milieu implique un processus de dissolution minérale, affectant en premier lieu les argiles fines (smectites). Les faibles valeurs de la CEC illustrent la perte notable de charges fixes liée à la dissolution partielle des smectites. Néanmoins, l’impact de l’altération en milieu acide sur la granulométrie apparait négligeable, car la teneur en argile dans les sols acides reste inchangée par rapport à 1929. Deux pistes sont envisagées pour expliquer ce constat : un processus de microdivision par l’altération de minéraux phyllosilicatés de taille limoneuse fine et leur transformation en particules argileuses, ou alors un processus de néoformation de phases secondaires à partir de Si, Al et/ou Fe libérés par dissolution d’argiles fines en milieu acide. Enfin, un processus d’agrégation à l’échelle des particules d’argile par le développement de liaisons fortes entre les particules d’argile et des phosphates-Al (ou –Fe) formés en milieu très acide est suspecté dans les sols sous phosphate d’ammoniaque conduisant à la sous-estimation de la fraction < 2 μm lors d’analyses granulométriques courantes.

La palette très étendue de propriétés physicochimiques des horizons de surface dans les 42 parcelles souligne un laps de temps court en pédologie pour leurs changements, d’ordre infra-centenaire. Pour assimiler ces changements opérés en surface au développement de processus pédologiques, il est nécessaire à la fois de suivre l’ampleur et la chronologie des évolutions par l’analyse d’échantillons de la collection historique et d’étendre l’étude des impacts aux horizons E, BT, et C profonds. Ces travaux sont actuellement en cours.

Effects of different cooking methods on some chemical and sensory properties of Galega kale

International Journal of Food Science and Technology

DOI: 10.1111/ijfs.13181

Kale (Brassica oleracea L. var. acephala) is rich in bioactive phytochemicals such as phenolic compounds and vitamins. However, cooking the plants can cause important changes in composition. The objective of this study was to investigate the effect of some domestic cooking processes (boiling, steaming, microwaving and pressure cooking) on several quality parameters of Galega kale. Boiling had the strongest effect on the antioxidant capacity (the IC50 was four times higher than in the fresh sample), total phenolics (losses of 76.4–77.9%) and colour (ΔE = 17.79–19.12). Microwaving caused the greatest loss of soluble solids (80.8–82.2%). Steaming seems to be the best method for retaining the nutrient and antioxidant capacity of kale (100% ash, 71–77.5% soluble solids, 100% antioxidant capacity, 67–71% total phenolics, 62–71% chlorophyll). However, steamed kale was awarded the lowest sensory scores, indicating the difficulty in reconciling nutritional value and sensorial quality. Use of discriminant statistical techniques enabled the classification of 100% of samples.

Optimization of the process of aromatic and medicinal plant maceration in grape marc distillates to obtain herbal liqueurs and spirits

Journal of the Science of Food and Agriculture

DOI: 10.1002/jsfa.7822

Herbal liqueurs are alcoholic beverages produced by the maceration or distillation of aromatic and medicinal plants in alcohol, and are also highly valued for their medicinal properties. The process conditions, as well as the number and quantity of the plants employed, will have a great influence on the quality of the liqueur obtained. The aim of this research was to optimize these important variables.

A Box–Benhken experimental design was used to evaluate the independent variables: alcohol content, amount of plant and time during the experimental maceration of plants in grape marc distillate. Four plants were assessed, with the main compound of each plant representing the dependent variable evaluated with respect to following the evolution of the maceration process. Bisabolol oxide A in Matricaria recutita L., linalool in Coriander sativum L. and eucalyptol in Eucalyptus globulus Labill. were quantified using a gas chromatography-flame ionization detector. Glycyrrhizic acid in Glycyrrhiza glabra L was determined using a high-performance liquid chromatography-diode array detector. Other dependent variables were also evaluated: total phenolic content, color parameters and consumer preference (i.e. appearance).

The experimental designs allowed the selection of the optimal maceration conditions for each parameter, including the preference score of consumers: 70% (v/v) of ethanol, 40 g L−1 plant concentration and a maceration process of 3 weeks. 

Second-generation bioethanol of hydrothermally pretreated stover biomass from maize genotypes

Biomass and Bioenergy, 90 (2016) 42–49

http://dx.doi.org/10.1016/j.biombioe.2016.03.029

Twelve maize genotypes, were agronomically evaluated and their stover hydrothermally pretreated in a temperature range of 210–225 °C to assess the effects of genotype and pretreatment severity on stover recalcitrance toward bioethanol conversion. Maize genotypes exhibited significant variation for biomass yield and all agronomic evaluated, while among all cell wall constituents measured in the unpretreated stover, only ash content showed differences among genotypes. The pretreatment severities assayed impacted most stover compositional traits, and the glucose recovered after enzymatic hydrolysis displayed a similar profile among genotypes with similar genetic background. Harsher pretreatment conditions maximized the potential cellulosic bioethanol production (208–239 L/t), while the mildest maximized the bioethanol from the hemicellulosic hydrolysates (137–175 L/t). Consequently, when both pentose and hexose sugars were considered, the total potential bioethanol produced at the lowest and highest pretreatment temperatures was similar in all genotypes (292–358 L/t), indicating that the lowest temperature (210 °C) was the optimal among all assayed. Importantly, the ranking of genotypes for bioethanol yield (L/ha) closely resembled the ranking for stover yield (t/ha), indicating that breeding for biomass yield would increase the bioethanol production per hectare regardless of the manufacturing process. Similarly, the genetic regulation of corn stover moisture is possible and relevant for efficient energy production as biomass moisture has a potential impact on stover transportation, storage and processing requirements. Overall, these results indicate that local landrace populations are important genetic resources to improve cultivated crops, and that simultaneous breeding for production of grain and stover bioethanol is possible in corn.

F sorption/desorption on two soils and on different by-products and waste materials

Environmental Science and Pollution Research (2016) 23, 14676–14685

DOI: 10.1007/s11356-016-6959-8

We used batch-type experiments to study F sorption/desorption on a forest soil, a vineyard soil, pyritic material, granitic material, finely and coarsely ground mussel shell, mussel shell calcination ash, oak wood ash, pine-sawdust, slate processing fines, and three different mixtures that included three components: sewage sludge, mussel shell ash, and calcined mussel shell or pine wood ash. The three waste mixtures, forest soil, pyritic material, and shell ash showed high sorption capacity (73–91 % of added F) and low desorption, even when 100 mg F L−1 was added. All these materials (and to a lower extent wood ash) could be useful to remove F from polluted media (as certain soils, dumping sites, and contaminated waters). The vineyard soil, the granitic material, mussel shell, slate fines, and pine-sawdust were less effective in F removal. In most cases, sorption data fitted better to the Freundlich than to the Langmuir equation. These results can be useful to program the correct management of the soils, by-products, and waste materials assayed, mostly in situations where F concentrations are excessive and F removal should be promoted.

As (V)/Cr (VI) pollution control in soils, hemp waste, and other by-products: competitive sorption trials

Environmental Science and Pollution Research

DOI: 10.1007/s11356-016-7108-0

We study As(V)/Cr(VI) competitive sorption on a forest soil, a vineyard soil, pyritic material, mussel shell, pine bark, oak ash, and hemp waste, adding variable As(V) and Cr(VI) concentrations or displacing each pollutant with the same concentration of the other. When using variable concentrations, As(V) showed more affinity than Cr(VI) for sorption sites on most materials (sorption up to >84 % on oak ash and pyritic material). The only exception was pine bark, with clearly higher Cr(VI) sorption (>90 %) for any Cr(VI)/As(V) concentration added. Regarding the displacement experiments, when As(V) was added and reached sorption equilibrium, the subsequent addition of equal Cr(VI) concentration did not cause relevant As displacement from oak ash and pyritic material, indicating strong As bindings, and/or low competitive effects. When Cr(VI) was added and reached sorption equilibrium, the subsequent addition of equal As(V) concentration caused Cr(VI) displacement from all materials except pine bark, indicating weak Cr bindings. In view of these results, oak ash and the pyritic material could be used to remove As(V) in concentrations as high as 6 mmol L−1, even in the presence of a wide range of Cr(VI) concentrations, whereas pine bark could be used to remove Cr(VI) concentrations as high as 6 mmol L−1. The other materials assayed (including hemp waste, studied for the first time as As(V) and Cr(VI) bio-sorbent) cannot be considered appropriate to remove As(V) and/or Cr(VI) from polluted media.

Production et caractérisation d’une nouvelle boisson alcoolisée distillée produite à partir de grande myrtille (Vaccinium corymbosum L.)

Fruits, 2016, vol. 71(4), 215-220

http://dx.doi.org/10.1051/fruits/2016013

La culture d’espèces de baies sous-utilisées et leur transformation en produits à haute valeur ajoutée, tels que les spiritueux à base de fruits, pourraient avoir un effet bénéfique sur l’économie des régions rurales et défavorisées des montagnes d’Espagne. La production d’une boisson alcoolisée distillée à partir de grandes myrtilles ou bleuets n’a pourtant jamais été signalée auparavant. La pâte de bleuet var. Bluecrop fermentée avec Saccharomyces cerevisiae IFI83, a été distillée en utilisant un système de distillation par train de vapeur d’eau; les composés volatils ont été déterminés par chromatographie en phase gazeuse. Dans le distillat obtenu, les concentrations moyennes d’éthanol (45,3 mL 100 mL-1 distillat), de substances volatiles (317,1 g hL-1 alcool absolu, aa) et de méthanol (261,0 g hL-1 aa) étaient conformes aux spécifications que le Conseil européen (règlement 110/2008) fixe pour ces composés. De plus, les rapports [3-méthyl-1-butanol/2-méthyl-1-propanol] et [2-méthyl-1-propanol/1-propanol] ont été de 2,60 et 1,34, respectivement, indiquant que la boisson alcoolisée distillée a une bonne qualité organoleptique. Les résultats suggèrent que la grande myrtille peut être utilisée avec succès pour la production d’un nouveau spiritueux de bonne qualité organoleptique et sanitaire pour les consommateurs.

Proteome changes in Garnacha Tintorera red grapes during post-harvest drying

LWT - Food Science and Technology, 69 (2016) 608–613

http://dx.doi.org/10.1016/j.lwt.2016.02.026

Fruit raisining is accompanied by changes in composition due to the joint action of water loss and modifying enzymes. Cell walls in grape berries form a barrier against diffusion of aromatic and polyphenolic compounds that influence wine quality. In this work, fresh and post-harvest dried grape samples of Vitis vinifera L. Garnacha Tintorera variety were compared in terms of proteome. The main change observed during raisining was over-expression from 14 to 47% of proteins involved in pathogen- and stress-resistance mechanisms, whereas metabolism-related proteins or those involved in the transcription and synthesis of other proteins decreased, respectively, from 43 to 27% and from 29 to 13%. These changes are important in the functional qualities and stability of the sweet wines obtained, since affect interactions with other macromolecules or metabolites.

Terpenoid trans-caryophyllene inhibits weed germination and induces plant water status alteration and oxidative damage in adult Arabidopsis

Plant Biology

DOI: 10.1111/plb.12471

trans-Caryophyllene (TC) is a sesquiterpene commonly found as volatile component in many different aromatic plants. Although the phytotoxic effects of trans-caryophyllene on seedling growth are relatively explored, not many information is available regarding the phytotoxicity of this sesquiterpenes on weed germination and on adult plants. The phytotoxic potential of TC was assayed in vitro on weed germination and seedling growth to validate its phytotoxic potential on weed species. Moreover, it was assayed on the metabolism of Arabidopsis thaliana adult plants, through two different application ways, spraying and watering, in order to establish the primary affected organ and to deal with the unknown mobility of the compound. The results clearly indicated that TC inhibited both seed germination and root growth, as demonstrated by comparison of the ED50 values. Moreover, although trans-caryophyllene-sprayed adult Arabidopsis plants did not show any effect, trans-caryophyllene-watered plants became strongly affected. The results suggested that root uptake was a key step for the effectiveness of this natural compound and its phytotoxicity on adult plants was mainly due to the alteration of plant water status accompanied by oxidative damage.

Cheese whey: A cost-effective alternative for hyaluronic acid production by Streptococcus zooepidemicus

Food Chemistry, 198, (2016) 54–61

http://dx.doi.org/10.1016/j.foodchem.2015.11.062

This study focuses on the optimisation of cheese whey formulated media for the production of hyaluronic acid (HA) by Streptococcus zooepidemicus. Culture media containing whey (W; 2.1 g/L) or whey hydrolysate (WH; 2.4 g/L) gave the highest HA productions. Both W and WH produced high yields on protein consumed, suggesting cheese whey is a good nitrogen source for S. zooepidemicus production of HA. Polysaccharide concentrations of 4.0 g/L and 3.2 g/L were produced in W and WH in a further scale-up to 5 L bioreactors, confirming the suitability of the low-cost nitrogen source. Cheese whey culture media provided high molecular weight (>3000 kDa) HA products. This study revealed replacing the commercial peptone by the low-cost alternative could reduce HA production costs by up to a 70% compared to synthetic media.

Structural and thermo-rheological analysis of solutions and gels of a β-lactoglobulin fraction isolated from bovine whey

Food Chemistry, 198 (2016) 45–53

http://dx.doi.org/10.1016/j.foodchem.2015.11.090

A β-Lactoglobulin fraction (r-βLg) was isolated from milk whey hydrolysates produced with cardosins from Cynara cardunculus. The impact of the technological process on the r-βLg structure and how in turn this determined its heat-induced gelation was investigated. Results were analysed taking pure β-Lg (p-βLg) as control sample. The process induced changes in the r-βLg native conformation causing exposure of hydrophobic groups, lower thermal stability and also, shorter thermal treatments needed to give rise to non-native and aggregated species.

At pH 3.2, r-βLg and p-βLg solutions exhibited two gelation steps, with the advantage that r-βLg protein may form stable gels at lower temperature than p-βLg. At pH 7.2, a specific thermo-viscoelastic stability to 73 °C was found, which corresponded to the gel point in both protein solutions. The difference was that while for p-βLg solution in sol state δ < 45° (solid-like), however for r-βLg solution δ > 45° (fluid-like).

Build-up of carbon fractions in technosol-biochar amended partially reclaimed mine soil grown with Brassica juncea

Journal of Soils and Sediments

May 2016, Volume 16, Issue 5, pp 1529–1537

DOI: 10.1007/s11368-016-1358-9

Soil organic carbon (SOC) and its labile fractions are strong determinants of physical, chemical and biological properties. The objective of the present work was to evaluate the effects of organic amendments (technosol made of wastes and biochar) and Brassica juncea L. on the soil C fractions in a reclaimed mine soil.

The studied soil was from a former copper mine that was subsequently partially reclaimed with vegetation and wastes. A greenhouse experiment was carried out to amend the mine soil with different proportions of technosol and biochar mixture and planting B. juncea. B. juncea plants can tolerate high levels of metals and can produce a large amount of biomass in relatively short periods of time.

The results showed that with the addition of biochar and wastes, soil pH increased from 2.7 to 6.18, SOC from undetectable to 105 g kg−1 and soil total nitrogen (TN) from undetectable to 11.4 g kg−1. Amending with wastes and biochar also increased dissolved organic carbon (DOC) from undetectable to 5.82 g kg−1, carbon in the free organic matter (FOM) from undetectable to 30.42 g kg−1, FAP (carbon in fulvic acids removed with phosphoric acid) from undetectable to 24.14 g kg−1 and also increased the humification ratio, the humification index, the polymerisation rate and the organic carbon in the humified fractions (humic acids, fulvic acids and humin). Soils amended and vegetated with B. juncea showed lower FOM values and higher humification index values than the soils amended only with biochar and wastes.

This study concludes that the combined addition of wastes and biochar has a greater potential for both increasing and improving organic carbon fractions in mine soils. The authors recommend the application of biochar and technosol made of wastes as a soil amendment combined with B. juncea on soils that are deficient in organic matter, since they increased all of the SOC fractions in the studied copper mine soil.

Temporal and spatial changes in soil micronutrients in managed Nothofagus pumilio forest of Tierra del Fuego, Argentina

Environmental Earth Sciences (2016) 75:738

DOI: 10.1007/s12665-016-5470-3

Soil organic components are important factors in the quality and productivity of forest ecosystems. Timber harvesting reduces plant cover and the amount of organic matter in forest floor layer, increases surface runoff, soil erosion and alters microclimatic conditions over large areas. These changes can have important implications for nutrient cycling dynamics and soil organic matter mineralization. Fueguian temperate forests of Nothofagus pumilio (lenga) have been intensely harvested for the last decades, mainly by shelterwood-cut silvicultural system. Harvesting removes nutrients contained in logs from the site, modifies light, temperature and soil humidity, constraining nutrient cycling process. In this study, we evaluate available copper (Cua), zinc (Zna), iron (Fea), and manganese (Mna) concentrations and reservoirs in stands that represent a chronosequence and their respective primary forests (controls): stands cut 1 year ago, stands cut 5–10 years ago, and stands harvested more than 50 years ago. Concentrations of Zna and Cua in primary forest were 39.9 and 2.6 mg/kg, and increased in harvested sites to 60.5 and 3.2 mg/kg, respectively. Fea and Mna concentrations showed similar ranges in both harvested and control sites. Recent harvested sites showed the highest Cua concentrations. Micronutrient reservoirs showed similar ranges in both harvested and primary forests. We concluded that micronutrient availability changes at short term after forest harvesting; thus, the inclusion of soil fertility assessment in forest management plans should be incorporated to preserve the fertility of lenga forests soils and ensure sustainability.

Changes in Cd, Cu, Ni, Pb and Zn Fractionation and Liberation Due to Mussel Shell Amendment on a Mine Soil

Land Degradation and Development 27 (2016) 1276–1285

DOI: 10.1002/ldr.2505

Mining activities are related to relevant environmental pollution issues that should be controlled. We used sequential extractions to fractionate Cd, Cu, Ni, Pb and Zn retained on unamended or mussel shell-amended mine soil samples, all of them treated with a mixture of the five heavy metals (total metal concentration of 1·57 mmol L−1), after 1, 7 and 30 days of incubation. In addition, we used the stirred flow chamber technique to study the release of each of the five heavy metals from these different unamended and shell-amended soil samples. The results indicate that the shell amendment caused a decrease in the most soluble fraction, while increasing the most recalcitrant (least mobile) fraction. With equivalent implications, the stirred flow chamber experiments showed that mussel shell amendment was associated to a decrease in heavy metal release and increased retention. The highest mussel shell dose and incubation time caused the most relevant changes in pH values and thus in metal retention, also indicating the importance of pH modifications in the mechanism of retention acting in the amended samples. In view of these results, the use of mussel shell amendment can be encouraged to increase heavy metal retention in acid mine soils, in order to minimise risks of environmental pollution. 

Study of metal transport through pine bark for reutilization as a biosorbent

Chemosphere 149 (2016) 146–153

http://dx.doi.org/10.1016/j.chemosphere.2016.01.087

The potential utilization of pine bark as a biosorbent for the treatment of metal-contaminated soils and waters has been evaluated in transport experiments using laboratory columns. Solutions containing the metals Cu, Pb, Zn, Ni or Cd, each one individually and at three different concentrations (2.5, 10 and 25 mM) were tested. Pine bark affected metal transport and the breakthrough curves, producing a reduction of their concentrations in the solution and a clear retardation with respect to an inert tracer. At metal concentrations equal to 2.5 mM, 100% of the assayed elements were removed from the solution in the pine bark column. At the 10 mM metal concentration, the percentage of metals retained fell to 38–67% of the amount added, whereas at the 25 mM metal concentration, only 16–43% was retained. In all cases, the highest retention capacity corresponded to Pb, and the lowest to Zn, whereas Cu, Cd and Ni produced intermediate comparable results. The analysis of the pine bark within the columns after the transport experiment showed that the metals entering the column adsorb progressively until a saturation concentration is reached in the whole column, and only then they can be released at significant concentrations. This saturation concentration was approximately 70 mmol kg−1 for Cd, Ni and Zn, 100 mmol kg−1 for Cu, and 125 mmol kg−1 for Pb. Overall, our experiments have shown the high effectiveness of pine bark to retain the assayed metals in stable forms of low mobility.

Influence of pH on viscoelastic properties of heat-induced gels obtained with a β-Lactoglobulin fraction isolated from bovine milk whey hydrolysates

Food Chemistry, 219, 2017, 169–178

http://dx.doi.org/10.1016/j.foodchem.2016.09.137

A β-Lactoglobulin fraction (r-βLg) was isolated from whey hydrolysates produced with cardosins from Cynara cardunculus. The impact of the hydrolysis process on the r-βLg structure and the rheological properties of heat-induced gels obtained thereafter were studied at different pH values. Differences were observed between r-βLg and commercial β-Lg used as control. Higher values for the fluorescence emission intensity and red shifts of the emission wavelength of r-βLg suggested changes in its tertiary structure and more solvent-exposed tryptophan residues. Circular dichroism spectra also supported these evidences indicating that hydrolysis yielded an intermediate (non-native) β-Lg state.

The thermal history of r-βLg through the new adopted conformation improved the microstructure of the gels at acidic pH. So, a new microstructure with better rheological characteristics (higher conformational flexibility and lower rigidity) and greater water holding ability was founded for r-βLg gel. These results were reflected in the microstructural analysis by scanning electron microscopy.

Contributions of a compost-biochar mixture to the metal sorption capacity of a mine tailing

Environmental Science and Pollution Research

February 2016, Volume 23, Issue 3, pp 2595–2602

DOI: 10.1007/s11356-015-5489-0

One technique applied to restore degraded or contaminated soils is to use amendments made of different types of waste materials, which in turn may contain metals such as Cu, Pb and Zn. For this reason, it is important to determine the capacity of the soil to retain these materials, and to compare the sorption capacity between an amended soil and another unamended soil. The aim of this study was to determine the mobility and availability of these metals in the soil after applying the amendment, and how it affected the soil’s sorption capacity. Sorption isotherms were compared with the empirical models of Langmuir and Freundlich to estimate the sorption capacity. The overall capacity of the soils to sorb Cu, Pb or Zn was evaluated as the slope Kr. The amendments used in this study were a mixture made of compost and biochar in different proportions (20, 40, 60, 100 %), which were applied to the mine tailing from a settling pond from a copper mine. The mine tailing that were amended with the mixture of compost and biochar had a higher sorption capacity than the mine tailing from the unamended pond, and their sorption isotherms had a greater affinity towards Cu, Pb and Zn than the mine tailing that was studied. Therefore, the results obtained show that adding a mixture of compost and biochar favours the retention of Cu, Pb and Zn in mine tailing.

Assessing the influence of technosol and biochar amendments combined with Brassica juncea L. on the fractionation of Cu, Ni, Pb and Zn in a polluted mine soil

Journal of Soils and Sediments

February 2016, Volume 16, Issue 2, pp 339–348

DOI: 10.1007/s11368-015-1222-3

Soil metal pollution is a widespread problem around the world and remediation of these soils is difficult. The objective of this study was to investigate the effect of two different strategies on the chemical fractions of metals in a soil of a depleted copper mine: (1) amending with a mixture of a technosol made of wastes and biochar and (2) amending combined with planting vegetation (Brassica juncea).

A 3-month greenhouse experiment was carried out to evaluate the effects of organic amendments and vegetation on the metal fractionation of Cu, Ni, Pb and Zn in a mine soil of the depleted copper mine at Touro (Spain). We compared the influence of organic amendments alone (technosol + biochar) and combined with mustard plants (Brassica juncea L.).

The results showed that amending with a technosol made of wastes promoted plant growth (from 0.7 to 2.9 g of biomass produced) and reduced the CaCl2-extractable metal concentration in soil, reduced the mobility factor of Cu from 18.3 to 1.6, Ni from 47.5 to 2.3 and Pb from 17.9 to 2.1, and also reduced the concentration of metals in the mobile soil fractions. It was not possible to grow up Brassica juncea plants in the untreated settling pond soil due to the extremely degraded conditions of that soil. However, the application of the used technosol increased the Pb and Zn pseudototal concentrations in the amended soils.

We conclude that the combination of amending with wastes and planting B. juncea provides little additional benefit for remediating a metal-polluted soil compared with incorporation of wastes alone.

Contribution of waste and biochar amendment to the sorption of metals in a copper mine tailing

CATENA
Volume 137, February 2016, Pages 120–125
http://dx.doi.org/10.1016/j.catena.2015.09.010

One technique applied to restore degraded or contaminated soils is to use amendments made of different types of waste materials, which in turn may contain metals such as Cu, Pb and Zn. For this reason it is important to determine the capacity of the soil to retain these materials, and to compare the sorption capacity between an amended soil and another unamended soil. The aim of this study was to determine the chemical behaviour of these metals in the soil after applying the amendment, and how it affected the soil's sorption capacity. Another aim was to study the contribution of contaminating elements from the amendment itself. The amendments used in this study were a mixture made of waste material (sewage sludges, sludges from an aluminium plant, ash, food industry wastes, and sands from a wastewater treatment plant) and biochar (biomass of Acacia dealbata) (97%:3%) in different soil/amendment proportions. The soil was from a mine tailing. The mine tailings were amended with the mixture of waste and biochar which had a higher sorption capacity than the soil from the pond. The samples with amendment had a greater affinity for Cu, Pb and Zn than the mine soil. The results obtained show that adding a mixture made of waste and biochar favours the retention of Cu, Pb and Zn in mine tailing from metal mines.